When equals in talents and contributing capability get together they get down to business.
The question of doing elaborate agreements, putting things down on paper, getting signatures on the dotted lines, doesn't come up. No lies, no complicated contracts.
The entire focus is on building art, shipping stuff and at times, even changing the world. Not on writing CYA documents or haggling about who gets an extra five percent on profits.
Every time you hear excessive stress on agreements or documents even before you've started something gorgeous it is often a sign of insecurity.
Or an indication that one or more (or all) parties are incompetent.
I am not saying every agreement is a sign of incompetence but if you can connect on a shared cause that is larger than pettiness, you'll see magic.
People working for free to get the project live, people contributing in open source projects they like, entrepreneurs putting in personal money to keep the business alive, developers responding to support requests on forums.
Because all parties are competent. All parties are just as capable of making it on their own. All parties don't have insecurities about being diddled out of a deal.
Or maybe, its because everyone understands, that it isn't a deal that they are working on.
It's a dream.
And that's fundamentally different.